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Changes to Ubiquiti UniFi AP AC Lite TVS Diode Replacement Introduction

Edit by Maxime Rousseau

Edit approved by Adam O'Camb

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Introduction
This guide outlines steps needed to repair an Ubiquiti Unifi AP AC Lite (model UAP-AC-LITE) access point which '''does not power on''', and is identified by the PoE injector has having a power fault. (Blinking white on the PoE injector.) [ … ] In some cases, affected units may have their center LEDs flash dimly when the reset button is held pressed in with the POE power in place. This may only be visible if the board is out of it's chassis. [ … ] The UAP-AC-LITE contains an over-voltage protection circuit driven by a unidirectional TVS diode. While this diode is not a fuse, it's expected failure mode is to short, and diverts power away from the rest of the board. This short is also detected by the PoE injector, which causes it to not deliver power. [ … ] In this guide will show how to: [ … ] # Disassemble the UAP-AC-LITE # Test if the over voltage protection TVS diode has failed # Remove and replace the broken diode
This guide outlines steps needed to repair an Ubiquiti Unifi AP AC Lite (model UAP-AC-LITE) access point which '''does not power on''', and is identified by the PoE injector has having a power fault. (Blinking white on the PoE injector.) [ … ] In some cases, affected units may have their center LEDs flash dimly when the reset button is held pressed in with the POE power in place. This may only be visible if the board is out of it's chassis. [ … ] The UAP-AC-LITE contains an over-voltage protection circuit driven by a unidirectional TVS diode. While this diode is not a fuse, it's expected failure mode is to short, and diverts power away from the rest of the board. This short is also detected by the PoE injector, which causes it to not deliver power. [ … ] In this guide will show how to: [ … ] # Disassemble the UAP-AC-LITE # Test if the over voltage protection TVS diode has failed # Remove and replace the broken diode